From patchwork Thu Feb 11 10:16:15 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: =?utf-8?b?SsO8cmdlbiBHcm/Dnw==?= X-Patchwork-Id: 12082685 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-18.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1804FC433E0 for ; Thu, 11 Feb 2021 10:18:06 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id C877264E38 for ; Thu, 11 Feb 2021 10:18:05 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C877264E38 Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from list by lists.xenproject.org with outflank-mailman.83800.156859 (Exim 4.92) (envelope-from ) id 1lA92s-0001oJ-9C; Thu, 11 Feb 2021 10:17:58 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 83800.156859; Thu, 11 Feb 2021 10:17:58 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1lA92s-0001o6-4H; Thu, 11 Feb 2021 10:17:58 +0000 Received: by outflank-mailman (input) for mailman id 83800; Thu, 11 Feb 2021 10:17:57 +0000 Received: from all-amaz-eas1.inumbo.com ([34.197.232.57] helo=us1-amaz-eas2.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1lA92r-0001VI-7w for xen-devel@lists.xenproject.org; Thu, 11 Feb 2021 10:17:57 +0000 Received: from mx2.suse.de (unknown [195.135.220.15]) by us1-amaz-eas2.inumbo.com (Halon) with ESMTPS id c958570c-1b54-4414-a274-bdc203af6dae; Thu, 11 Feb 2021 10:17:42 +0000 (UTC) Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 6FD2CAF49; Thu, 11 Feb 2021 10:17:41 +0000 (UTC) X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: c958570c-1b54-4414-a274-bdc203af6dae X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1613038661; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=nYiBLOOS0jKaGXZR/xdp5WHTi+5sOW1v2m88NDrZNbI=; b=LmkY0cY/xUPQabBZ2K6py6iwlNSohSvZqtVGIKhgfs/Vd+e3i0HPowZRhK5GJgyUl5o28/ Lx47YRJ3EXvR1/z8sPJDmrvUc6rf00u386Gf1+f8cdN9vhlSbjkIEU7foEmfSwD4BZQf/a zldb9aBFKnXvuTux4U/p6Gw35AZbFbs= From: Juergen Gross To: xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org Cc: Juergen Gross , Boris Ostrovsky , Stefano Stabellini , Andrew Cooper , Jan Beulich Subject: [PATCH v2 7/8] xen/evtch: use smp barriers for user event ring Date: Thu, 11 Feb 2021 11:16:15 +0100 Message-Id: <20210211101616.13788-8-jgross@suse.com> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20210211101616.13788-1-jgross@suse.com> References: <20210211101616.13788-1-jgross@suse.com> MIME-Version: 1.0 The ring buffer for user events is local to the given kernel instance, so smp barriers are fine for ensuring consistency. Reported-by: Andrew Cooper Signed-off-by: Juergen Gross Reviewed-by: Jan Beulich --- drivers/xen/evtchn.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/xen/evtchn.c b/drivers/xen/evtchn.c index a7a85719a8c8..421382c73d88 100644 --- a/drivers/xen/evtchn.c +++ b/drivers/xen/evtchn.c @@ -173,7 +173,7 @@ static irqreturn_t evtchn_interrupt(int irq, void *data) if ((u->ring_prod - u->ring_cons) < u->ring_size) { *evtchn_ring_entry(u, u->ring_prod) = evtchn->port; - wmb(); /* Ensure ring contents visible */ + smp_wmb(); /* Ensure ring contents visible */ if (u->ring_cons == u->ring_prod++) { wake_up_interruptible(&u->evtchn_wait); kill_fasync(&u->evtchn_async_queue, @@ -245,7 +245,7 @@ static ssize_t evtchn_read(struct file *file, char __user *buf, } rc = -EFAULT; - rmb(); /* Ensure that we see the port before we copy it. */ + smp_rmb(); /* Ensure that we see the port before we copy it. */ if (copy_to_user(buf, evtchn_ring_entry(u, c), bytes1) || ((bytes2 != 0) && copy_to_user(&buf[bytes1], &u->ring[0], bytes2)))